#!/bin/bash

set -e
[ -n "$DEBUG" ] && set -x

# check requirements
for tool in mbsync notify-send python awk gdbus iconez; do
	if ! command -v "$tool" >/dev/null; then
		printf '%s: %s not installed but required\n' "$(basename "$0")" "$tool" >&2
		exit 1
	fi
done

maildir="${HOME}/mail"
cachefile=${XDG_CACHE_HOME}/mailsync.lastrun

accounts=(gnzler hu)
list=
verbose=
while getopts a:lvh opt; do
	case "${opt}" in
	a) accounts=("${OPTARG}") ;;
	l) list=1 ;;
	v) verbose=1 ;;
	h | ?)
		printf "usage: %s [-h] [ACCOUNT...]\n" "$(basename "$0")"
		printf "\n"
		printf "  -a ACCOUNTS, accunts to sync (default: \"%s\")\n" "${accounts[@]}"
		printf "  -l list mail\n"
		printf "  -v be verbose"
		printf "\n"
		exit 2
		;;
	esac
done
shift $((OPTIND - 1))

if [ -n "$1" ]; then
	accounts=("$@")
fi

notifysend() {
	local summary=$1
	local body=$2
	local ico
	shift 2

	if ! printf "%s" "$*" | grep -- "-i" >/dev/null; then
		ico="📨 "
	fi

	# -i /usr/share/icons/mdi/scalable/email-plus.svg \
	notify-send $@ \
		-a mailsync \
		-c audible \
		"${ico:-}${summary}" "${body}"
}

decode() {
	python -c 'import sys;import email.header;print(("".join(list(map(lambda s: s[0] if (type(s[0]) == str) else s[0].decode(s[1] or "utf-8"), email.header.decode_header(((sys.stdin.readlines() or [""])[0]).strip()))))))'
}

handle_msg() {
	local msg=$1
	local from
	local subject
	local listid
	local ico

	from=$(sed ':a; N; $!b a; s/\n\s\{1,\}/ /g' "${msg}" | awk '/^From:/{print}' | cut -d: -f2 | decode)
	subject=$(sed ':a; N; $!b a; s/\n\s\{1,\}/ /g' "${msg}" | awk '/^Subject:/{print}' | cut -d: -f2 | decode)
	listid=$(sed ':a; N; $!b a; s/\n\s\{1,\}/ /g' "${msg}" | awk '/^List-ID:/{print}' | cut -d: -f2 | decode)
	if [ -n "${listid}" ]; then
		subject="${subject}\n<span alpha='90%' size='small'>~> $(echo "${listid}" | sed -e 's|<|\&lt;|g' -e 's|>|\&gt;|g')</span>"
		ico="$(iconez -sn email-multiple-outline)"
	else
		ico="$(iconez -sn email-receive-outline)"
	fi
	notifysend "${from}" "${subject}" -i "${ico}" -t 2000
}

list_msg() {
	local acct=$2
	local args=(-type f -not -name '\.*')
	local cachefile="${cachefile}.${acct}"

	find "${maildir}"/"${acct}"/{INBOX,lists}/new/ "${args[@]}" 2>/dev/null || true

	# local cur_or_new=${1:-new}
	# if [ "${cur_or_new}" = "new" ]; then
	# 	find "${maildir}"/"${acct}"/{INBOX,lists}/"${cur_or_new}"/ "${args[@]}" 2>/dev/null || true
	# else
	# 	find "${maildir}"/"${acct}"/*/"${cur_or_new}"/ "${args[@]}" 2>/dev/null || true
	# fi
}

run_notify() {
	local acct=$1
	local new_mail

	new_mail=$(list_msg new "${acct}")
	if [ -n "${new_mail}" ]; then
		local num
		num="$(echo "${new_mail}" | grep -c INBOX)"
		# always print INBOX messages
		for msg in $(echo "${new_mail}" | grep INBOX); do handle_msg "$msg"; done

		# everything else, limit to 5, just print the count otherwise
		num="$(echo "${new_mail}" | grep -c -v INBOX)"
		notifysend "${acct}: new" "Found ${num} new mail" -i "$(iconez -sn email-receive-outline)"
		[ "${num}" -gt 5 ] && return
		for msg in $(echo "${new_mail}" | grep -v INBOX); do handle_msg "$msg"; done
	fi
}

run_sync() {
	local acct=$1

	# exit if we're already running
	pgrep mbsync >/dev/null && {
		echo "mbsync is already running."
		notifysend "mailsync stopped" "mbsync is already running" -i "$(iconez -sn email-off-outline)"
		return
	}

	# persistent notification
	id=$(notifysend "${acct}: fetching new mail..." "running mbsync" -i "$(iconez -sn email-sync-outline)" --print-id --expire-time=0)

	mbsync_args=
	[ -n "${verbose}" ] && mbsync_args="--verbose"
	mbsync $mbsync_args --config="$HOME/.config/mbsyncrc" "$acct"
	clear-notification "$id"
	# create cachefile
	touch "${cachefile}.${acct}"

	# index new messages
	command notmuch >/dev/null 2>&1 && notmuch new
}

# only list new mail, don't sync
if [ -z "${accounts[*]}" ]; then
	echo "no account specified" >&2
	exit 1
fi

for acct in "${accounts[@]}"; do
	(
		if [ -n "${list}" ]; then
			list_msg "${list}" "${acct}"
			exit 0 # exit ()& subshell
		fi
		run_sync "${acct}"
		run_notify "${acct}"
	) &
done

wait